Electrocardiographic manifestations of pulmonary embolism

The electrocardiogram (ECG) may be entirely normal in the patient with pulmonary embolism (P/E); alternatively, any number of rhythm and/or morphologic abnormalities may be observed in such a patient. The abnormal ECG may deviate from the norm with alterations in rhythm, in conduction, in axis of the QRS complex, and in the morphology of the P wave, QRS complex, and ST segment/T wave. The electrocardiographic findings associated with PE are numerous, including arrhythmias (sinus tachycardia, atrial flutter, atrial fibrillation, atrial tachycardia, and atrial premature contractions), nonspecific ST segment/T wave changes, T wave inversions in the right precordial leads, rightward QRS complex axis shift and other axis changes, S1Q3 or S1Q3T3 pattern, right bundle branch block, and acute cor pulomnale. This review focuses on the ECG and the various abnormalities seen in the patient with PE.     

Difficulties in diagnosis of infarction of the right ventricular myocardium

About half of the patients with symptoms of inferior acute myocardial infarction (MI) of the left ventricle (LV) are found to have proximal occlusion of the dominant right coronary artery presented on ECG by ischemia or infarction of the right ventricular wall. Hypotension, high pressure in the jugular veins and, in some cases, shock with clear lung fields--typical clinical picture of right ventricular MI. The diagnosis begins with ECG picture of LV lower wall ischemia (rise of ST wave in leads II, III and aVF) with possible emergence of a pathological wave Q and right ventricular ischemia (rise of ST wave in leads V3R-V6R and its depression in leads V2-V4). Echo-CG and balanced radioventriculography were used for verification of the diagnosis, precise localization of the myocardial lesion. Therapy of patients with right ventricular MI consists in maintenance of adequite preload of the right ventricle, inotropic support and control over atrioventricular conduction.     

Right ventricular infarction: specific requirements of management.

The principal cause of right ventricular infarction is atherosclerotic proximal occlusion of the right coronary artery. Proximal occlusion of this artery leads to electrocardiographically identifiable right-heart ischemia and an increased risk of death in the presence of acute inferior infarction. Clinical recognition begins with the ventricular electrocardiographic manifestations: inferior left ventricular ischemia (ST segment elevation in leads II, III and aVF), with or without accompanying abnormal Q waves and right ventricular ischemia (ST segment elevation in right chest leads V3R through V6R and ST segment depression in anterior leads V2 through V4). Associated findings may include atrial infarction (PR segment displacement, elevation or depression in leads II, III and aVF), symptomatic sinus bradycardia, atrioventricular node block and atrial fibrillation. Hemodynamic effects of right ventricular dysfunction may include failure of the right ventricle to pump sufficient blood through the pulmonary circuit to the left ventricle, with consequent systemic hypotension. Management is directed toward recognition of right ventricular infarction, reperfusion, volume loading, rate and rhythm control, and inotropic support.     

心电图在肺栓塞诊断中的研究

目的 通过对肺栓塞及有相似临床表现的几组疾病心电图的对比,试图了解肺栓塞心电图的特点和心电图在肺栓塞诊断及鉴别诊断中的应用及意义.方法 共入选364例肺栓塞病例.其中肺栓塞组197例,对照组共167例.对照组分为:1组冠心病心力衰竭组70例,2组原发性高血压心力衰竭组47例,3组急性肺损伤/急性呼吸窘迫综合征组50例.对364例患者的心电图等临床资料进行分析.结果 肺栓塞组心电图出现电轴右偏、顺钟向转位、右束支传导阻滞、肺型P波、V1导联S波粗顿或挫折等与对照组相比明显增加,差异有统计学意义;S1Q3T3、胸前导联T波倒置出现的比率也是肺栓塞组最高,差异有统计学意义.结论 肺栓塞患者心电图的表现以右心负荷增加和反射性的冠状动脉缺血为主要表现;S1Q3T3可能是电轴右偏的表现;每一个指标的敏感性和特异性都难以承担诊断和鉴别诊断的重任;动态观察心电图对肺栓塞的诊断意义重大.     

A potential diagnostic pitfall in acute chest pain: Massive pulmonary embolism mimicking acute STEMI

Background

Pulmonary embolism (PE) represents a clinical challenge for clinicians because of nonspecific presentations, including dyspnea, chest pain, and tachycardia. The immediate 12-lead electrocardiogram (ECG) is commonly used to facilitate differential diagnosis of acute chest pain. Although relative rare, massive pulmonary embolism could induce ST segment elevation and mimic acute myocardial infarction.

A young man with recurrent syncopes, right bundle branch block and ST segment elevation.

We report on the case of a 33-year-old man with recurrent syncopes appearing suddenly due to sustained monomorphic ventricular tachycardias. The electrocardiogram (ECG) showed a right bundle branch block pattern and ST segment elevation in the precordial leads V1 to V2, not explained by ischemia, electrolyte disturbances, toxic ingestion, or structural heart disease (coronary and right ventricle angiograms as well as biopsies of the right ventricle were normal). ECG image was compatible with the so-called Brugada syndrome, first described in 1992. This entity is very rare. Missed diagnosis can be disastrous because life-threatening ventricular arrhythmias often develop in patients.     

Aborted sudden death in a patient with a structurally normal heart: the Brugada syndrome

We report a 37-year-old man with documented aborted sudden death. After resuscitation, the patient showed no structural heart disease but the ECG showed a right bundle-branch block with a descending ST segment elevation in leads V(1) and V(2). After transient normalization of the ECG, the administration of ajmaline led to spontaneous development of the distinct descending ST segment elevation in the right precordial leads and therefore to the diagnosis of Brugada syndrome. The incidence of sudden cardiac death among these patients is high. The only treatment is an implantable cardioverter-defibrillator (ICD). The Brugada syndrome should therefore be borne in mind in the differential diagnosis of sudden death.     

Electrocardiographic changes in Takotsubo cardiomyopathy

Introduction: Takotsubo cardiomyopathy (TC) is a unique transient nonischemic cardiomyopathy that mimics acute myocardial infarction (MI). The aim of our study was to evaluate electrocardiographic changes in patients with TC, including the frequency of ST elevation and other abnormalities. Methods : Eleven patients were retrospectively identified from echocardiography database. All patients underwent coronary angiography and fulfilled the Mayo criteria for diagnosis of TC during the period November 2005 to September 2010. Standard 12‐lead electrocardiograms recorded daily during the first week of hospitalization, after onset of symptoms were analyzed. Results: Eight of 11 patients were found to have ST elevation, of which two patients had ST depression in reciprocal leads. No patient had ST elevation in lead V1, most likely reason being that wall‐motion abnormalities in TC rarely extend to the region faced by lead V1. Pathological Q waves were found in five patients, of which two patients had transient Q waves, suggesting less myocardial damage. All 11 patients had T‐wave inversion; eight of these patients had diffuse symmetric T‐wave inversion, extending beyond the perfusion territory of any single coronary artery. QTc interval prolongation was found in 10 patients. All patients had left ventricular ejection fraction between 25% and 35% on presentation, which could not be predicted by the extent of electrocardiogram (ECG) changes. Conclusion: ECG changes in TC are distinctive and differ from those typically seen in acute anterior MI. The ECG abnormalities described may be important clues for the clinician to suspect diagnosis of TC in the right clinical setting. (PACE 2011; 34:1278–1282)     

十二导联心电图对左主干病变导致急性冠状动脉综合征的诊断价值

目的探讨十二导联心电图对左主干病变导致急性冠状动脉综合征（ACS）的诊断价值。方法37例ACS患者根据冠状动脉造影结果分为A组（左主干病变导致ACS组）17例和B组（左前降支近段病变导致ACS组）20例,2组患者胸痛发作时均行十二导联心电图检查,分析冠状动脉病变血管与相应心电图变化的关系。结果A组在Ⅱ、Ⅲ、aVF、V2、V3、V4、V5、V6导联上相应ST段压低的发生率高于B组（P〈0．05或P〈0．01）。A组ST段在aVR、V1导联抬高并aVF、V2、V4导联压低发生率高于B组（P〈0．05）。结论十二导联心电图上aVR、V1导联ST段抬高并aVF、V2、V4导联压低对ACS患者左主干病变有较好的阳性预测价值。     

心电图在急性肺动脉栓塞诊断中的价值

目的 评估心电图对急性肺动脉栓塞(肺栓塞)的诊断价值.方法 回顾性分析43例既往无心肺疾病的急性肺栓塞患者住院首次、溶栓后及出院前系列心电图变化.结果 ①入院时首次心电图:心动过速26例(60.47%),右束支传导阻滞10例(23.26%);V1导联和V1～V2导联、V1～V3导联、V1～V4导联、V1～V5导联、V1～v6导联T波倒置分别为34例(79.70%)、20例(46.52%)、12例(27.91%)、9例(20.93%)、7例(16.28%)和2例(4.65%);SⅠ＞0.1 mV、TⅢ倒置、QⅢ和SⅠQⅢTⅢ分别为23例(53.49%)、21例(48.84%)、27例(62.79%)和20例(46.52%).②溶栓后心电图:心动过速消失20例(76.9%),右束支传导阻滞消失4例(40%),胸前导联T波倒置加深4例,SⅠ变浅、QⅢ减小或消失、TⅢ倒置变浅或直立11例.③出院前心电图:心动过速消失;胸前导联T波直立数增加,ST段回基线,QⅢ进一步减小或消失,TⅢ倒置变浅或直立.结论 急性肺栓塞心电图变化多变,需动态观察并密切结合临床加以识别.     

Asymptomatic pulmonary embolus masquerading as acute anteroseptal myocardial infarction

Pulmonary embolism (PE) is an uncommon and often overlooked cause of ST-segment elevation on the electrocardiogram (ECG). Emergent echocardiography has been cited as a means to rapidly distinguish acute myocardial infarction from PE. However, both of these conditions can present with focal wall motion abnormalities. We report a case of a 51-year-old asymptomatic male who presented to our emergency department with anterior ST-segment elevation and right-heart strain on an ECG. The clinical diagnosis of ST elevation myocardial infarction was in doubt, and an echocardiogram was obtained while the patient was in the emergency department. Although a focal area of hypokinesia was observed on echocardiography, cardiac catherization did not demonstrate any evidence of acute coronary occlusion. A computed tomographic angiogram of the chest was subsequently obtained, which demonstrated evidence of submassive pulmonary emboli. Our case highlights the limited utility of emergent echocardiography in cases of ST-segment elevation.     

A case of myocardial infarction due to acute left main coronary artery occlusion presenting with peculiar electrocardiographic changes

Myocardial infarction (MI) due to acute obstruction of the left main coronary artery (LMCA) occlusion is a medical emergency, requiring early and prompt diagnosis and revascularization, and unless it is treated, it will frequently result in cardiogenic shock, which has a high fatality rate. Our case focused on a patient, who was transferred to our hospital relatively late due to peculiar ECG. He had acute MI, and was in cardiogenic shock. ECG is the easiest diagnostic method in the early diagnosis of the acute coronary syndromes and in deciding on the early invasive intervention in the high risk group. Before he was sent to us, the patient had an ECG showing right bundle branch block (RBBB) and a AVR ST segment elevation. At the time of the urgent coronary angiography, it was noticed that the LMCA was totally occluded. This case has been presented in order to emphasize that peculiar changes might bring about devastating consequences as in our rare case, showing acute left main coronary artery occlusion, and ST segment elevation only in the AVR on the 12-lead ECG along with upward deflection of ST segment vector might be critical for accurate diagnosis.     

正常人右胸头胸导联心电图特征

目的评价一种新的右胸导联心电图：头胸（ＨＣ）导联心电图的应用价值。方法对６４例正常人描记同时间、同部位的Ｗｉｌｓｏｎ导联（Ｖ３Ｒ～Ｖ７Ｒ）和ＨＣ导联（Ｈｖ３Ｒ～Ｈｖ７Ｒ）图形。结果两种导联方法心电图均无ＳＴ段抬高；ＨＶ５Ｒ～ＨＶ７Ｒ直立Ｐ波多于Ｖ５Ｒ～ｖ７Ｒ（Ｐ均（０．０５）；病理Ｑ波（Ｑ≥１／４Ｒ，ｔ＞０．０４秒）或Ｑｒ型波在Ｖ４Ｒ为６％，Ｖ５Ｒ为５６％，Ｖ６Ｒ为６２％，Ｖ７Ｒ为６５％，Ｔ波直立者仅１２％，然而ＨＣ导联均为Ｒ型或石型，Ｔ波直立者达８８％。Ｑ波出现率在Ｖ５Ｒ和ＨＶ５Ｒ、Ｖ６Ｒ和ＨＶ６Ｒ、Ｖ７Ｒ和ＨＶ７Ｒ间呈显著差异（Ｐ均＜０．００１），直立Ｔ波出现率在Ｖ３Ｒ～Ｖ７Ｒ和ＨＶ３Ｒ～ＨＶ７Ｒ间亦有明显差异（Ｐ波＜０．０１）。根据图形特征，ＨＣ导联右胸图形可分为３型：（１）ＨＶ３Ｒ～ＨＶ７Ｒ呈Ｒ型伴Ｔ波直立者占５５％；（２）ＨＶ３Ｒ～ＨＶ５Ｒ为ｒＳ型，ＨＶ６Ｒ和ＨＶ７ＲＲ型伴Ｔ彼直立者占３３％；（３）ＨＶ３Ｒ～ＨＶ７Ｒ均呈ｒＳ型伴Ｔ波平坦者占１２％。结论由于ＨＣ导联右胸心电图在健康人群中表现为正常的Ｐ－ＱＲＳ－Ｔ波群，故有益于右室疾病的诊断。     

急性下壁心肌梗死患者的临床特点分析

目的 分析研究急性下壁心肌梗死患者的临床特点. 方法 将急性下壁心肌梗死患者100例根据冠状动脉造影结果分为两组:76例为右冠状动脉(RCA)闭塞(A组),24例为左回旋支冠状动脉(LCX)闭塞(B组). 结果 心电图ST段抬高STⅢ>STⅡ及ST段压低STAVL>ST I A组显著高于B组(均P<0.05);ST段抬高STⅢ0.1 mV A组显著高于B组(P<0.05);胸前导联V1～6ST段压低患者中,合并左前降支冠状动脉(LAD)病变的患者显著高于胸前导联V1～6ST段无压低者(P<0.05);左心室射血分数(LVEF)A组[(51±14)%]显著低于B组[(57±10)%](P<0.05);合并右心室心肌梗死A组显著高于B组(P<0.05);急性下壁心肌梗死患者总的住院病死率6%,均为A组,但心源性休克、心力衰竭、Ⅱ、Ⅲ度房室传导阻滞,室性心动过速/心室颤动及住院病死率,两组差异均无统计学意义(均P>0.05);死亡者中心源性休克占83.3%. 结论 心电图Ⅲ、Ⅱ、I、AVL、及V4R导联ST段变化能预测急性下壁心肌梗死相关血管,急性下壁心肌梗死患者伴胸前导联ST段压低提示LAD病变,RCA闭塞所致下壁心肌梗死LVEF低于LCX闭塞者,心源性休克为死亡主要原因.     

Electrocardiographic findings and myocardial damage in acute myocarditis detected by cardiac magnetic resonance

Delayed-contrast-enhancement (DCE) magnetic resonance imaging (MRI) can identify areas of myocardial damage in patients with acute myocarditis (AM). The aim of this study was to assess the electrocardiographic findings in AM diagnosed by DCE-MRI. Eighty-one patients (72 men, 35 ± 13 years) with AM were prospectively enrolled. All of them underwent MRI and 12-lead-ECG recordings. In the admission electrocardiogram (ECG 1), as well as in that obtained 48 h later (ECG 2), the following parameters were analyzed: rhythm, PR, QRS, and QTc-intervals, intraventricular conduction, abnormal Q waves, ST segment elevation, and T wave inversion. On admission, 77 patients (95%) were in sinus rhythm, while four patients (6%) manifested severe arrhythmias. No difference between ECG 1 and ECG 2 was observed regarding abnormal Q waves, PR, QRS, and QTc-intervals. Electrocardiogram 1 was normal in 26 patients (32%, normal ECG group), and abnormal in 55 patients (68%, abnormal ECG group). ST elevation was found in 46 patients (57%), inverted T wave in seven patients (9%) and left bundle branch block (LBBB) in two patients (3%). Areas of DCE suggesting AM were found in each patient. No relationship concerning the location of the involved region (s) was found between ECG (leads with ST/T abnormalities) and MRI (areas showing DCE). The ECG in AM can either be normal or reflect abnormalities including arrhythmias, LBBB, ST segment elevation, and T wave inversion. The location of myocardial involvement deduced on the basis of ECG leads showing ST/T changes is not in close relationship with the areas of ventricular damage detected by MRI.     

Intravenous administration of class I antiarrhythmic drug induced T wave alternans in an asymptomatic Brugada syndrome patient

A 53-year-old man with an abnormal ECG was referred to the Nihon University School of Medicine. The 12-lead ECG showed right bundle branch block and saddleback-type ST elevation in leads V1-V3 (Brugada-type ECG). Signal-averaged ECG showed positive late potentials. Double ventricular extrastimuli (S1: 500 ms, S2: 250 ms, S3: 210 ms) induced VF. Amiodarone (200 mg/day) was administered for 6 months and programmed ventricular stimulation was repeated. VF was induced again by double ventricular stimuli (S1: 600 ms, S2: 240 ms, S3: 170 ms). Intravenous administration of class Ic antiarrhythmic drug, pilsicainide (1 mg/kg), augmented ST-T elevation in leads V1-V3, and visible ST-T alternans that was enhanced by atrial pacing was observed in leads V2 and V3. Visible ST-T wave alternans disappeared in 15 minutes. However, microvolt T wave alternans was present during atrial pacing at a rate of 70/min without visible ST-T alternans.     

Additional electrocardiographic leads in the ED chest pain patient: right ventricular and posterior leads

In the evaluation of the patient with chest pain, the 12-lead electro cardiogram is a less-than-(ECG) perfect indicator of acute myocardial infarction (AMI), particularly when used early in the course of the acute ischemic event; this relative insensitivity for AMI results from many different issues, including a less-than-optimal imaging of certain areas of the heart. It has been suggested that the sensitivity of the 12-lead ECG can be improved if 3 additional body surface leads are used in selected individuals. Acute posterior (PMI) and right ventricular myocardial infarctions are likely to be underdiagnosed, because the standard lead placement of the 12-lead ECG does not allow these areas to be assessed directly. Additional leads frequently used include leads V(8) and V(9), which image the posterior wall of the left ventricle, and lead V(4R), which reflects the status of the right ventricle. The standard ECG coupled with these additional leads constitutes the 15-lead ECG, the most frequently used additional lead ECG in clinical practice. The use of the additional leads might not only confirm the presence of AMI, but also provide a more accurate reflection of the true extent of myocardial damage.     

Therapeutic hypothermia after out-of-hospital cardiac arrest due to Brugada syndrome

A 56-year-old man was admitted to our hospital after successful resuscitation for out-of-hospital cardiac arrest. Electrocardiogram on admission showed right bundle branch block and ST segment elevation in leads V1-3. Subsequent intravenous infusion of isoproterenol rapidly resolved ST segment elevation, suggesting Brugada syndrome. Therapeutic hypothermia, that was performed with a target temperature of 34.0 degrees C did not induce ST segment elevation in leads V1-3. The J-ST segment elevation rather became much more normal, suggesting a beneficial effect of mild therapeutic hypothermia. Serial ECG showed the temporal variation of ST segment elevation, and pilsicainide challenge test showed the occurrence of ST segment elevation, confirming the diagnosis of Brugada syndrome. Clinical observation suggested that mild therapeutic hypothermia reversed the Brugada phenotype through the prevention of fever as well as being indicated for cerebral protection after cardiac arrest. In conclusion, therapeutic hypothermia with a temperature of 34.0 degrees C can be used safely in Brugada syndrome.     

Misplacing V1 and V2 can have clinical consequences

The precordial electrocardiogram (ECG) leads V1 and V2 are often misplaced. Such misplacement usually involves placing these leads too high on the chest. The resulting ECG may generate erroneous ECG patterns: e.g. incomplete right bundle branch block, anterior T wave inversion, septal Q waves, ST-segment elevation. These features may falsely suggest acute or old cardiac ischemia, pulmonary embolism, or a type-2 Brugada pattern. On rare occasion, conversely, high placement of V1 and V2 may reveal a true type-1 Brugada pattern. The emergency clinician needs to be aware of the possibility of lead misplacement, and should know how to suspect it based on unusual P wave morphology in V1 and V2.     

Analyzing Prominent T Waves and ST-segment Abnormalities in Acute Myocardial Infarction

Background: Hyperacute T waves and the non-concave appearance of the ST segment are early changes that may be seen on the electrocardiogram (ECG) in an acute myocardial infarction (AMI) patient. There are specific morphological changes in these ECG findings that can help distinguish them from other conditions with similar ECG patterns. The differential diagnosis of prominent T waves and ST-segment elevation is well known, however, certain tools to distinguish ECG patterns with various etiologies have been developed and proven useful to the emergency physician. Objectives: 1) To discuss and review the more common differential diagnosis of prominent T waves and how to identify the hyperacute T wave of AMI. 2) To review the distinction and determination of a concave and non-concave ST segment that may be initially overlooked. Case Report: A 42-year-old woman with minimal cardiac risk factors developed an ST-segment elevation myocardial infarction (STEMI) that illustrates the evolution of early and classic ECG changes associated with her infarct. Conclusions: The classic STEMI is ingrained in the emergency physician's mind, however, sometimes other lesser known and obvious ECG patterns can present early on in the evolution of disease, and these morphological patterns should be identified and treated accordingly.